Voltage regulator



Dec. 25, 1945. A. TOELLE ET AL 2,391,526

VOLTAGE REGULATOR Ff led Jan. 14, 1944 C. R. Sulei- I INV ENTOR BY (2M4K i Patented Dec. 25, 1945 VOLTAGE REGULATOR August Toelle and Condo R.Salet, Detroit,

Mich, assignors to Ford Motor Company, Dearborn, Mich., a corporation ofDelaware Application January 14, 1944, Serial No. 518,224

ZClalms.

This invention relates to an apparatus for a contact breaker used in avoltage regulator for controlling the flow of electricity in electricalequipment in motor vehicles and the like.

In vehicle electrical installations, a voltage reg-' the life of theregulator contacts. including improvements both in the materials fromwhich contacts are made and the use of auxiliary devices which willreduce the spark potential eifective when the circuit is broken.Following the first course, a number of contact alloys have beendeveloped which have been found highly resistant. However, due to theshortages arising from wartime demands, many of the alloying elementsare no longer available and it is necessary to use substitutes which donot have the inherent resistance to erosion through arcing that theother metals possessed.

Since it is no longer possible to obtain these highly resistant alloys,recourse must be had to auxiliary means which will reduce the arcingeffect and thereby render the available contact alloys at least asefiicient'and durable as those previously used. Thepresent inventioncontemplates an extremely simple method of reducing the arcing efiectbetween the contacts of a voltage regulator and doing it with apparatuswhich is simple and easy to construct, entirely automatic in operationand certainly as durable and efficlent as the prior voltage regulatorconstruction. An advantage of the present invention is that means areprovided to subdivide-as it werethe breaking of the contact and togovern the resistance of the circuit, over these subdivisionsintermediate the breaking of contact at the regulator; and proportioningthis resistance so that the arcing potential over any one subdivision ismaterially reduced. It thus follows that the life of the contacts isproportionately increased and their durability enhanced without anydecrease of electrical efiiciency. The outstanding result is a net gainin contact life without necessitating the use of the rarer alloyingmetals, which are intrinsically better but which are no longeravailable.

With these and other objects in view, the invention consists in thearrangement, construction and combination of the various parts of theimproved device, as described in the specification, claimed in theclaims, and illustrated in the accompanying drawing, in which:

Figures 1, 2, 3 and 4 are diagrammatic representations of successivestages in the operation of a voltage generator employing this invention.

Figure 5 is an elevation of the particular voltage regulator unit.

Referring to Figure 5, the regulator Ill comprises an L-shaped frame IIon which is mounted a coil I2 wound on the core I3 and an armature I4hingedly supported by the leaf spring ['5. A moving contact point I6 ismounted on the lower arm ll of the armature It and a fixed contact pointI8 is insulatedly supported on an extension 9 secured to the frame I I.So far, it will be recognized that the construction is entirelyconventional.

The novelty in the present regulator is the provision ofa plurality, inthis case two, intervening contact points l9 and 20 arranged be-"alignment with the contact points I6 and I8. It

is thus apparent that a series of contacts is provided and 'that whenthe circuit is closed, points I8, I8, I9 and 20 are all in contact andthat provision may be made for opening the circuit by successivelybreaking contact between adjacent contact points.

Reference is now made to Figures 1 through 4 illustrating the electricalconnections in the circuit with the several components of the regulator.Similar reference characters indicate identical elements as describedwith respect to Figure ,5 and, in addition, the regulator is showninterposed in a typical automotive electrical circuit in which 25 is thebattery, 26 the generator and 21 the ground. However, the structure of,the regulator is much simplified and those of its elements which arenot germane to the present invention such as the compensating means andthe 'like are not shown. It will be noted that a resistance 28 isconnected acrossthe principal contacts I6 and I8, and that thisresistance is further tapped by leads to the intervening contact pointsI9 and 20 to form, in reality, three separate resistances 29, 30 and 3Iconnected in resistance 28.

successive steps by which the vibratoropens and I be divided in as manyincrements as-desired.

series. In Figure 1, the four contacts are shown together and thecircuit is closed directly through them and no current flows through thecombined Figure 2 shows the first of the in it the armature M-is beingattracted down-i wardly to the coil l2 and the contact between points l8and 20 has been broken while that at 20, I9 and i6 is maintained. Thecurrent now flows through the first of the separate resistl0 ances,portion 29, which is shown in heavier line and thence through 20, I9 andI6. Figure '3- shows the next step in which the descent of the armaturecontinues and in which contact 20 has moved away from contact l9.However, contacts I 9 and .IGremain in engagement and the cur rent flowsthrough two of the separate, resistances, portions 29 and 30, which are,as, stated above, arranged in series and thence throughflB and I9.Figure 4 shows the final stage (in the descent. of the armature id inwhich all of the contact points are disassociatedand in which anycurrent across the contacts must fiow through the combined'resistance 28comprising all three of the separate resistances 29, 30 and 3| connectedin series. This, of course, reduces the effective fiux of the coil l2and the spring l5 returns the armature to its uppermost positioneffecting successive contact between the four contact points until thecondition shown in 5 is resumed and the vibratory cycle can be repeated.As a practical matter, the combined resistance 28 should aggregate about100 ohms for a 24 volt system and 50 ohms for 12 voits and this may Itwill be understood that this cycle is repeated continuously and initself is practically instantaneous. It is furtherrecognized that in theconventional construction, the breaking of contact order shown.

between thepoints is inevitably accompanied by some arcing, which, intime, must have a deleterious effect on the contacts and will destroytheir electrical efiiciency. It is believed clear from the descriptionof the device how the construction utilized cuts down this arcing to apoint at which .45 it is no longer objectionable and permits the use ,1of metals for the contact points of lesser dura bility'. .In short,rather than concentr'ating the.

arcing at any one pair of contact points, the {operation is conductedsuccessively and resistances are interposed between successive contactsso that the. arcing potential between iany two is reduced to a point atwhich no damage is caused. Following the first four figures in order, it[is clear that'the interposition of the successive resistances betweenthe opening contact points reduces the potentialto a point atwhich nodamage will occur; T0 effect this sequence, it is essential that thecontacts open in" precisely the Therefore, means must be provided toprevent, for example, contact I5 open? ing from contact it initially asthe armature moves downwardly, or contact l9 openingjrom',

'contact 20, To obtain this sequence, it is essenl tial that the spring15 and the spring shanks 2! of the'contact points l9 and 20 be carefullyequated so that as the armature moves downwardly, the initial break willoccur between contacts 20 and I8 and that the resiliency of spring shank2| of contact 20 be sufficient to maintain connections between contacts'20, i9 and I6. Similarly, as the armature continues its course, contact20 will come to rest and thereafter the resiliency in the shank 2| ofcontact l9 must be sufficient to keep contact I?! in connection with anL-shap'ed contact l6 until the armature has moved to a.

position at which these two contacts would normally break. Therefore, itis apparent that there may be a graduated resiliency between the threesprings to effect the desired sequence ofopera tion and overcome theinherent inertia of the contacts which otherwise would tend, at worst,

to permit opening in the inverse order.

It is believed that operation of the advantages in the presentconstruction will be clear from the foregoing. The :electri'calconnections have not,

been indicated inFigure 5 or shown in full in the\ other figures as theywill be clear to those skilled in'the art since the circuit and thebreaker construction are conventional apart from the multicontactfeaturedescribed. The successive introduction of increments oi resistance willreduce the\ park potential and'reduce the amount so that it can nolonger be deleterious to the individual contacts} Thus, although thenumber of contact surfaces is multiplied, the life and emciency of thedevice, as-a whole, is increased many times over those \employing butasingle pair of contacts; and permits, as an alternative, the use ofless suitable; alloy materials in the contact points themseles without asacrifice in operatin efficiency, I

Some changes may be made in the arrangement, construction andcombination of the various parts of the improved construction withoutdeparting from the spirit ofthe invention, and it is the intention tocover by the claims such changes as may be reasonably includedwlthin thescope,thereof.

The invention claimed is:

1. In a voltage regulator, an L-shaped base, an electromagnet fixedlymounted on one leg of said'base anti spaced from the other leg thereof,

movable armature pivotally supported at the end of said other leg ofsaid base, one leg of said armature overlying (andv actuated by saidelectromagnet, a fixed contact supported on said base between said otherleg thereofand said electromagnet, a cooperating contact on the otherleg of said armature positioned between said other leg of said base andsaid fixed contact, a plurality of auxiliary spring leaf supportedcontacts between said fixed contact and said cooperating contact andsuccessively aligned therewith to form a series of interengagingcontacts adapted to permit electrical connection therethrough when saidarmature isremote from said electromagnet, substantially equalincrements of resistance connected in series between each of said.contacts, and means efiective on the moving of said cooperating contactas said armature. approaches said electromagnet to break initially a theconnection between said fixed contact and the adjacentauxiliary contactbefore breaking the connection between said cooperating contact and itsadjacent auxiliary contact. 2, In a voltage regulator, a base, anelectromagnet fixedly mounted on said base, a movable armature pivotallysupported on said base cooperating with and actuated by saidelectromagnet, a fixed contact on said base, a cooperating contact onsaid armature, a plurality offauxiliary contacts mounted on leaf springsinsulatedl y supported on said fixed contact between said fixed contactand said cooperating contact and successively aligned therewith, saidauxiliary contacts having opposite contact faces and adapted connectiontherethrough and to open successively and provide an alternativeconnection through increments of resistance connected in seriesthereoetween, said leaf springs supporting said auxiliary contacts beingso proportioned as to resiliency that on movement of said cooperatingcontact in response to movement of said armature from its remoteposition, the connection between said fixed contact and its immediatelyadjacent auxiliary contact will be broken initially, and breaking of theconnection between successive adjacent auxiliary contacts will follow,and the breaking of connection between said cooperating contact and itsimmediately adjacent auxiliary contact will occur in that order.

AUGUST TOELLE. CORADQ R. SALEI'.

